Acrylonitrile butadiene styrene/multi-walled carbon nanotubes nanocomposite foams for electromagnetic interference shielding with optimized performance

The advancement of polymeric nanocomposite foams for electromagnetic interference (EMI) shielding can be credited to two main factors: the multiple deflections of the incoming electromagnetic waves within the shield and the formation of conductive pathways by the nanofillers. In this research, chemical foaming is employed in injection molding machine to create foams made of acrylonitrile butadiene styrene (ABS) and multi-walled carbon nanotubes (MWCNTs). By incorporating a 1 wt% concentration of MWCNT, applying a pressure time of 2 s, and allowing for a cooling time of 60 s, foamed nanocomposite samples demonstrated a remarkable total EMI shielding effectiveness (SE) of SE T = 16.25 dB. This SE value surpassed the EMI SE values of the remaining samples across the X-band frequency range. Upon comparing foamed samples of pure and nanocomposite materials with identical cell density, it was observed that the enhancement of SE T for the nanocomposite foamed sample reached 21.2% in contrast to the pure foamed sample operating at 11.52 GHz. The research revealed that incorporating a microcellular structure had a notable impact on the electrical conductivity, relative permittivity, dielectric loss, relative permeability, and magnetic loss in ABS/MWCNT nanocomposites. Furthermore, the nanocomposite foams demonstrated significantly greater EMI SE in comparison to their solid counterparts.